Multimedia files such as digital images, videos and music typically represent 90% or more of the data that is stored on the disk drive a typical personal computer. As understood herein, methods exist for backing up personal multimedia files but most them are expensive and require user effort and knowledge on how to execute. Even worse, some of the back-up mechanisms still entail significant risk. For example, backing up personal videos to a second drive on the same PC is risky if the PC is stolen. Backing up the files to a set of DVDs is risky in the case of a fire, and backing up to a single on-line backup service can be expensive and can also be risky should the on-line backup company go out of business.
As also understood herein, it is not always necessary to have an exact copy of a multimedia file be available as a backup copy, because even if 5%-10% of the pixels in a backup photograph are different from the original, for instance, it is unlikely that a significant difference will be apparent to a casual viewer. Likewise, it can be difficult to discern the difference between an original video and a backup version of that video that is missing a relatively small percentage of the original frames.